Master manufacturing method, master, and optical body

ABSTRACT

There is provided a new and improved master manufacturing method, master, and optical body enabling more consistent production of optical bodies having a desired haze value, the master manufacturing method including: forming a first micro concave-convex structure, in which an average cycle of concavities and convexities is less than or equal to visible light wavelengths, on a surface of a base material body that includes at least a base material; forming an inorganic resist layer on the first micro concave-convex structure; forming, on the inorganic resist layer, an organic resist layer including an organic resist and filler particles distributed throughout the organic resist; and etching the organic resist layer and the inorganic resist layer to thereby superimpose and form on the surface of the base material a macro concave-convex structure and a second micro concave-convex structure.

CROSS REFERENCE TO PRIOR APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/545,857 (filed on Jul. 24, 2017), which is a National Stage PatentApplication of PCT International Patent Application No.PCT/JP2016/060555 (filed on Mar. 30, 2016) under 35 U.S.C. § 371, whichclaims priority to Japanese Patent Application No. 2015-071844 (filed onMar. 31, 2015), which are all hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to a master manufacturing method, amaster, and an optical body.

BACKGROUND ART

Typically, with display devices such as televisions, and opticalelements such as camera lenses, in order to reduce surface reflectionsand increase transmitted light, an anti-reflection treatment isperformed on the light-incident surface. For example, one proposal forsuch an anti-reflection treatment is to laminate, onto thelight-incident surface, an optical body on which is formed a microconcave-convex structure in which the average cycle of the concavitiesand convexities is less than or equal to the visible light wavelengths(such as a moth-eye structure, for example).

At the surface having such a micro concave-convex structure, arefractive index changes gradually with respect to incident light, andthus a steep change in refractive index, which causes reflection, doesnot occur. Accordingly, forming such a micro concave-convex structure onthe light incident surface prevents reflection of incident light for awide wavelength region.

Regarding the method of forming a micro concave-convex structure at thenanometer scale, for example, Patent Literature 1 discloses a method ofperforming dry etching by using island-shaped nanoparticles as aprotective mask. Also, Patent Literature 2 and 3 disclose methods ofusing the anodic oxidation of an aluminum film to form a microconcave-convex structure having multiple sub-micrometer concavities inthe aluminum film. Furthermore, Patent Literature 4 discloses a methodof using electron-beam lithography to form a micro concave-convexstructure in which the average cycle of the concavities and convexitiesis less than or equal to a certain wavelength.

In addition, Patent Literature 1 and 2 also disclose that it is possibleto form a transfer product to which the micro concave-convex structurehas been transferred by pressing a structure on which has been formedsuch a micro concave-convex structure into a resin or the like.

Note that regarding a method of treating a structure on which has beenformed the micro concave-convex structure as a mold to form a transferproduct to which the micro concave-convex structure has beentransferred, for example, the technology disclosed in Patent Literature5 below is also known. Specifically, Patent Literature 5 discloses thatby pressing a roll-shaped mold, on the outer circumferential surface ofwhich a fine pattern has been formed, into a film or the like while alsorotating the mold, it is possible to transfer the fine pattern onto afilm of large surface area.

Also, in recent years, even higher optical characteristics are beingdemanded of optical bodies. From such a perspective, with PatentLiterature 2 to 4, the anti-reflection function described above as wellas an anti-glare function are conferred to an optical body.Specifically, with Patent Literature 2, there is prepared an aluminumfilm on the surface of which are distributed coarse crystal particles,and then anodic oxidation and etching are repeatedly performed on thealuminum film. With this arrangement, an aluminum film in which a microconcave-convex structure is superimposed onto the rough surface of thealuminum film is produced. Additionally, with Patent Literature 3 and 4,the surface of a substrate is roughened by a mechanical or chemicalmethod, and a micro concave-convex structure is superimposed onto therough surface. According to these technologies, an anti-glare functionis realized by the rough surface formed on the substrate, while ananti-reflection function is realized by the micro concave-convexstructure superimposed onto the rough surface.

CITATION LIST Patent Literature

Patent Literature 1: JP 2012-1000A

Patent Literature 2: JP 4916597B

Patent Literature 3: JP 2009-288337A

Patent Literature 4: JP 2009-128541A

Patent Literature 5: JP 2014-43068A

SUMMARY OF INVENTION Technical Problem

Meanwhile, the haze value is known as an evaluation indicator of ananti-glare function. The haze value is an indicator expressing theturbidity (cloudiness) of an optical body. As the haze value increases,the light-scattering properties of the optical body increase, and thusthe anti-glare function increases. Additionally, for optical bodymanufacturing technologies, there is demand to be able to consistentlymanufacture optical bodies having a desired haze value. However, theoptical bodies produced by the technologies disclosed in PatentLiterature 2 to 4 are problematic in that there is extremely largeindividual variation in the haze value. Accordingly, the presentinvention has been devised in light of the above problem, and anobjective of the present invention is to provide a new and improvedmaster manufacturing method, master, and optical body enabling moreconsistent production of optical bodies having a desired haze value.

Solution to Problem

According to an aspect of the present invention in order to achieve theabove object, there is provided a master manufacturing method,including: a first step of forming a first micro concave-convexstructure, in which an average cycle of concavities and convexities isless than or equal to visible light wavelengths, on a surface of a basematerial body that includes at least a base material; a second step offorming an inorganic resist layer on the first micro concave-convexstructure; a third step of forming, on the inorganic resist layer, anorganic resist layer including an organic resist and filler particlesdistributed throughout the organic resist; and a fourth step of etchingthe organic resist layer and the inorganic resist layer to therebysuperimpose and form on the surface of the base material a macroconcave-convex structure in which the average cycle of concavities andconvexities is greater than visible light wavelengths, and a secondmicro concave-convex structure in which the average cycle of concavitiesand convexities is less than or equal to visible light wavelengths. Anaverage grain size of the filler particles is greater than visible lightwavelengths. An etch rate of the filler particles is different from anetch rate of the organic resist.

Herein, the etch rate of the filler particles may be higher than theetch rate of the organic resist.

The average grain size of the filler particles may be from 2 μm to 15μm.

In the fourth step, the organic resist layer and the inorganic resistlayer may be etched by dry etching. An etching gas used when dry-etchingthe organic resist layer may be different from an etching gas used whendry-etching the inorganic resist layer.

The etching gas used when dry-etching the organic resist layer mayinclude a first etching gas and a second etching gas. The etch rate ofthe organic resist with respect to the first etching gas may be higherthan the etch rate of the inorganic resist layer with respect to thefirst etching gas. The etch rate of the organic resist with respect tothe second etching gas may be lower than the etch rate of the inorganicresist layer with respect to the second etching gas.

The etching gas used in the dry etching may include one or more types ofatoms selected from a group consisting of carbon atoms, fluorine atoms,oxygen atoms, and hydrogen atoms.

The first step may include a step of producing the base material body byforming a base material resist layer on the surface of the basematerial, and a step of forming the first micro concave-convex structurein the base material resist layer. The etch rate of the base materialresist layer may be different from the etch rate of the inorganic resistlayer.

The base material body may be made of the base material. The first stepmay include a step of forming a base material resist layer on thesurface of the base material, a step of forming a third microconcave-convex structure having a same arrangement pattern as the firstmicro concave-convex structure in the base material resist layer, and astep of forming the first micro concave-convex structure on the surfaceof the base material by etching the base material resist layer.

The second step may include a step of forming a first inorganic resistlayer on the first micro concave-convex structure, and a step of forminga second inorganic resist layer on the first inorganic resist layer.

According to another aspect of the present invention, there is provideda master manufactured by the above master manufacturing method.

According to another aspect of the present invention, there is providedan optical body, to which is transferred the macro concave-convexstructure and the second micro concave-convex structure formed on theabove master.

According to the above aspect of the present invention, by adjusting theaverage grain size and concentration of filler particles, the averagecycle of a macro concave-convex structure formed on a master can beadjusted. Furthermore, by adjusting factors such as the ratio of theetch rate of an organic resist and the etch rate of an inorganic resistlayer, the arithmetic average roughness of a second micro concave-convexstructure formed on the master may be adjusted. Consequently, an opticalbody having the desired arithmetic average roughness and average cyclecan be produced consistently. In addition, although described in detaillater, there is a correlation between the arithmetic average roughnessand average cycle of an optical body, and the haze value of the opticalbody. Consequently, an optical body having a desired haze value can beproduced more consistently.

Advantageous Effects of Invention

According to the present invention as described above, an optical bodyhaving a desired haze value can be produced more consistently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective diagram illustrating an exemplary appearance ofa master according to the present embodiment.

FIG. 2 is a cross-section diagram that schematically illustrates thesurface shape of a master.

FIG. 3 is a plan view that schematically illustrates the surface shapeof a master.

FIG. 4 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 5 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 6 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 7 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 8 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 9 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 10 is a cross-section diagram for explaining each step of a mastermanufacturing method.

FIG. 11 is a cross-section diagram for explaining a first modificationof a master manufacturing method.

FIG. 12 is a cross-section diagram for explaining a second modificationof a master manufacturing method.

FIG. 13 is a block diagram illustrating an exemplary configuration of anexposure device usable in the present embodiment.

FIG. 14 is a schematic diagram illustrating an example of a transferdevice using a master according to the present embodiment.

FIG. 15 is a cross-section diagram that schematically illustrates thesurface shape of an optical body.

FIG. 16 is a graph illustrating a correlation between Ra/Rsm and thehaze value.

FIG. 17A is a scanning electron microscopic (SEM) photograph of a masterproduced by Example 2. The magnification is 500×.

FIG. 17B is a photograph in which the magnification of FIG. 17A is setto 5000×.

FIG. 17C is a photograph in which the magnification of FIG. 17A is setto 20000×.

FIG. 18 is a schematic diagram illustrating an optical system thatmeasures the diffuse reflection spectrum.

FIG. 19 is a graph illustrating the diffuse reflection spectrum.

DESCRIPTION OF EMBODIMENTS

<1. Master>

[1.1. Structure of Master]

First, a configuration of a master 1 according to the present embodimentwill be described with reference to FIGS. 1 to 3. FIG. 1 is aperspective diagram illustrating an exemplary appearance of the master1, while FIG. 2 is a cross-section diagram that schematicallyillustrates the surface shape of the master 1, and FIG. 3 is a plan viewthat schematically illustrates the surface shape of the master. Notethat FIG. 2 is a cross-section diagram obtained by cutting the master 1by a plane that passes through the central axis of the master 1, and isalso parallel to the central axis. The horizontal direction in FIG. 3 isaligned with the circumferential direction of the master 1, while thevertical direction is aligned with the axial direction of the master 1.As illustrated in FIG. 1, the master 1 is a master used in a nanoimprintmethod, and has a hollow round cylindrical shape, for example. Themaster 1 may also have a round columnar shape, or another shape (forexample, a planar shape). However, in the case in which the master 1 hasa round columnar or hollow round cylindrical shape, a concave-convexstructure of the master 1 may be transferred seamlessly to a resin basematerial or the like with a roll-to-roll method. With this arrangement,an optical body 4 onto which the concave-convex structure of the master1 has been transferred (see FIG. 15) may be produced with highproduction efficiency. From such a perspective, the shape of the master1 is preferably a hollow round cylindrical shape or a round columnarshape. Note that the optical body 4 onto which a concave-convexstructure is transferred by the master 1 according to the presentembodiment is used as an anti-reflective film or the like, for example.Note that in FIG. 1, of a macro concave-convex structure 12 and a microconcave-convex structure 13 to be described later, only the microconcave-convex structure 13 is illustrated. In actuality, the macroconcave-convex structure 12 and the micro concave-convex structure 13are formed superimposed onto the surface of a base material 11.

As illustrated in FIG. 2, the master 1 according to the presentembodiment is provided with a base material 11, a macro concave-convexstructure 12 formed on the surface of the base material 11, and a microconcave-convex structure 13 (second micro concave-convex structure)superimposed onto the macro concave-convex structure 12.

The base material 11 is a glass body, for example, and specifically isformed from quartz glass. However, the base material 11 is notparticularly limited insofar as the SiO₂ purity is high, and may also beformed from a material such as fused quartz glass or synthetic quartzglass. The shape of the base material 11 is a hollow round cylindricalshape, but may also be a round columnar shape, or some other shape.However, as discussed above, the base material 11 preferably has ahollow round cylindrical shape or a round columnar shape.

The macro concave-convex structure 12 is a concave-convex structureformed on the base material 11, and as illustrated in FIG. 2, includesconvexities 121 which are convex in the film-thickness direction of thebase material 11, and concavities 122 which are concave in thefilm-thickness direction of the base material 11. The average cycle ofthe concavities and convexities of the macro concave-convex structure 12is greater than the visible light wavelengths (for example, exceeding830 nm), and preferably more than or equal to 1 μm and less than orequal to 100 μm. Consequently, the macro concave-convex structure 12forms what is called an anti-glare structure. The average cycle (=Rsm)of the macro concave-convex structure 12 is the arithmetic average valueof the distance P1 between neighboring convexities 121 and betweenneighboring concavities 122. Note that a method of calculating theaverage cycle is as follows, for example. Namely, multiple pairs ofneighboring convexities 121 and pairs of neighboring concavities 122 arepicked up, and the distance P1 therebetween is measured. Subsequently,the average cycle may be calculated by taking the arithmetic average ofthe measured values.

The micro concave-convex structure 13 is a concave-convex structuresuperimposed onto the macro concave-convex structure 12. As illustratedin FIG. 2, the micro concave-convex structure 13 includes concavities132 which are concave in the film-thickness direction of the basematerial 11, and convexities 131 which are positioned between mutuallyadjacent concavities 132 and 132. Note that in FIG. 2, multipleconvexities 131 are disposed with spacing between each other, but asillustrated in FIG. 3, the convexities 131 may also be adjacent to eachother. Also, as illustrated in the diagram, the micro concave-convexstructure 13 may also be disposed periodically on the base material 11.In the example of FIG. 3, the convexities 131 and the concavities 132are arranged in a staggered pattern. Specifically, on the surface of themaster 1, multiple tracks extending in the circumferential direction(for example, tracks T1 to T3) are disposed at equal intervals in theaxial direction, while the convexities 131 and the concavities 132 aredisposed at equal intervals in each track. Also, the convexities 131 inadjacent tracks are disposed offset from each other in thecircumferential direction by one-half of one of the convexities 131.

The average cycle of the concavities and convexities of the microconcave-convex structure 13 is less than or equal to the visible lightwavelengths (for example, less than or equal to 830 nm), preferably morethan or equal to 100 nm and less than or equal to 350 nm, and morepreferably more than or equal to 150 nm and less than or equal to 280nm. Consequently, the micro concave-convex structure 13 has what iscalled a moth-eye structure. Herein, if the average cycle is less than100 nm, there is a possibility that the formation of the microconcave-convex structure 13 may become difficult, which is notpreferable. Also, if the average cycle exceeds 350 nm, in the opticalbody 4 to which the concave-convex structure of the master 1 istransferred, there is a possibility that a diffraction phenomenon ofvisible light may occur, which is not preferable.

The average cycle of the micro concave-convex structure 13 is thearithmetic average value of the distance P2 (see FIG. 2) betweenneighboring convexities 131 and between neighboring concavities 132.Note that a method of calculating the average cycle is as follows, forexample. Namely, multiple pairs of neighboring concavities 132 and pairsof neighboring convexities 131 are picked up, and the distance P2therebetween is measured. Herein, as illustrated in FIG. 3, the distanceP2 is categorized into a track pitch PT and a dot pitch PD. The trackpitch PT is the distance P2 between the convexities 131 (or theconcavities 132) disposed in adjacent tracks, while the dot pitch PD isthe distance P2 between the convexities 131 (or the concavities 132)disposed in the same track. Subsequently, the average cycle may becalculated by taking the arithmetic average of the measured values. Notethat the average cycles of the various concave-convex structures in thepresent embodiment are measured by methods similar to the above.

Note that the two-dimensional arrangement of the micro concave-convexstructure 13 obviously is not limited to the example of FIG. 3. Forexample, the multiple rows of tracks in which the convexities 131 andthe concavities 132 are arranged may be straight or curved. Also, theconvexities 131 and the concavities 132 may be arranged not in astaggered pattern, but instead so that the convexities 131 and theconcavities 132 are positioned at the vertices of a rectangle, forexample. In this case, the convexities 131 and the concavities 132 arearranged in a rectangular lattice. Also, the micro concave-convexstructure 13 may be disposed randomly. Even in this case, the averagecycle of the micro concave-convex structure 13 is still required to beless than or equal to the visible light wavelengths.

As described above, the master 1 according to the present embodiment hasa structure in which the macro concave-convex structure 12 and the microconcave-convex structure 13 are superimposed onto the surface of thebase material 11. Consequently, the optical body 4 to which theconcave-convex structure of the master 1 has been transferred has asurface shape onto which a macro concave-convex structure 41 and a microconcave-convex structure 42 are superimposed (see FIG. 15). With thisarrangement, the optical body 4 is able to jointly exhibit an anti-glarefunction due to the macro concave-convex structure 12, and ananti-reflection function due to the micro concave-convex structure 13.

[1.2. Master Manufacturing Method]

Next, an example of a master manufacturing method will be described withreference to FIGS. 4 to 10.

(First Step)

First, as illustrated in FIG. 4, a base material resist layer 15 isformed (deposited) on the base material 11, for example. With thisarrangement, a base material body is produced. In other words, in thisexample, the base material body is made up of the base material 11 andthe base material resist layer 15. Subsequently, a first microconcave-convex structure, namely a micro concave-convex structure 15B,is formed in the base material resist layer 15. At this point, theresist constituting the base material resist layer 15 is notparticularly limited, and may be either an organic resist or aninorganic resist. Examples of organic resists include novolac-typeresist and chemically-amplified resist. Also, examples of inorganicresists include metallic oxides including one or multiple types oftransition metals such as tungsten (W) or molybdenum (Mo). However, inorder to conduct thermal reaction lithography, the base material resistlayer 15 preferably is formed with a thermo-reactive resist including ametallic oxide.

In the case of using an organic resist, the base material resist layer15 may be formed on the base material 11 by using a process such as spincoating, slit coating, dip coating, spray coating, or screen printing.Also, in the case of using an inorganic resist for the base materialresist layer 15, the base material resist layer 15 may be formed bysputtering.

Next, as shown in FIG. 5, by exposing part of the base material resistlayer 15 with an exposure device 200 (see FIG. 13), a latent image 15Ais formed on the base material resist layer 15. Specifically, theexposure device 200 modulates laser light 20, and irradiates the basematerial resist layer 15 with the laser light 20. Consequently, part ofthe base material resist layer 15 irradiated by the laser light 20denatures, and thus a latent image 15A corresponding to the microconcave-convex structure 13 may be formed in the base material resistlayer 15. The latent image 15A is formed in the base material resistlayer 15 at an average cycle less than or equal to the visible lightwavelengths.

Next, as illustrated in FIG. 6, by dripping a developing solution ontothe base material resist layer 15 in which is formed the latent image15A, the base material resist layer 15 is developed. With thisarrangement, the micro concave-convex structure 15B (first microconcave-convex structure) is formed in the base material resist layer15. Note that in the case in which the base material resist layer 15 isa positive resist, the exposed part which is exposed by the laser light20 (that is, the portion where the latent image 15A is formed) isremoved by the developing process, because the dissolution rate withrespect to the developing solution is increased compared to theunexposed part. In this case, a micro concave-convex structure 15B isformed in which the exposed part becomes the concavities, and theunexposed part becomes the convexities. On the other hand, in the casein which the base material resist layer 15 is a negative resist, theexposed part which is exposed by the laser light 20 has a lowerdissolution rate with respect to the developing solution compared to theunexposed part, and thus the unexposed part is removed by the developingprocess. In this case, a micro concave-convex structure 15B is formed inwhich the exposed part becomes the convexities, and the unexposed partbecomes the concavities.

(Second step)

Next, as illustrated in FIG. 7, an inorganic resist layer 17 is formed(deposited) on the micro concave-convex structure 15B (that is, on thebase material resist layer 15) so as to embed the micro concave-convexstructure 15B. The inorganic resist constituting the inorganic resistlayer 17 may be, for example, SiO₂, Si, diamond-like carbon (DLC), W,Mo, or a metallic oxide including one or multiple types of transitionmetals such as W and Mo. The inorganic resist layer 17 is formed on themicro concave-convex structure 15B by a method such as sputtering orchemical vapor deposition (CVD). In this way, in the present embodiment,the inorganic resist layer 17 is formed in a state in which the microconcave-convex structure 15B of the base material resist layer 15 stillremains. The reasons for this are as follows.

Namely, the inventors discovered that if the processes in the presentsecond step and thereafter are performed after forming a microconcave-convex structure 14 (see FIG. 12) on the base material 11, themicro concave-convex structure 13 is either not formed on the basematerial 11, or even if formed, the aspect ratio is greatly differentfrom the aspect ratio of the micro concave-convex structure 15B in somecases. This tendency is particularly noticeable in the case ofattempting to form a micro concave-convex structure 13 with a highaspect ratio (for example, 1 or greater). Note that the aspect ratio ofa micro concave-convex structure is the value obtained by dividing thedistance between the convexities or between the concavities (forexample, the distance P2 illustrated in FIG. 2) by the height of theconvexities or the depth of the concavities.

On the other hand, if the processes in the second step and thereafterare performed in a state in which the micro concave-convex structure 15Bof the base material resist layer 15 still remains, a microconcave-convex structure 13 having a desired aspect ratio can be formedconsistently on the base material 11. For this reason, in the presentembodiment, the inorganic resist layer 17 is formed in a state in whichthe micro concave-convex structure 15B of the base material resist layer15 still remains. Note that even in the case of forming the inorganicresist layer 17 after forming the micro concave-convex structure 14 onthe base material 11, according to a second modification describedlater, a micro concave-convex structure 13 having a desired aspect ratiocan be formed. The second modification will be described later.

At this point, the inorganic resist constituting the inorganic resistlayer 17 is selected so that the etch rate of the inorganic resist layer17 is different from the etch rate of the base material resist layer 15.As described later, since the inorganic resist layer 17 and the basematerial resist layer 15 are etched at the same time, in thehypothetical case in which both have the same etch rate, both will beetched equally. In this case, the micro concave-convex structure 13cannot be formed on the surface of the base material 11. For example, inthe case in which the base material resist layer 15 is made up of ametallic oxide such as tungsten oxide, it is sufficient for theinorganic resist layer 17 to be made up of SiO₂, Si, or the like.

The thickness of the inorganic resist layer 17 is not particularlylimited, and may be from 500 nm to 1500 nm, for example. Note that theinventors attempted to form an organic resist layer 19 described lateron the micro concave-convex structure 15B while omitting the inorganicresist layer 17. However, in this case, the micro concave-convexstructure 13 was not formed on the base material 11, even after etchingthe organic resist layer 19 and the like. The cause cannot be specifiedclearly, but is thought to be because of the organic resist 191 exertingsome kind of negative influence on the base material resist layer 15 andthe base material 11. On the other hand, in the case in which theinorganic resist layer 17 is interposed between the micro concave-convexstructure 15B and the organic resist layer 19 (the case of the presentembodiment), the micro concave-convex structure 13 can be formed on thebase material 11.

(Third Step)

Next, as illustrated in FIG. 8, the organic resist layer 19 is formed onthe inorganic resist layer 17. Herein, the organic resist layer 19includes an organic resist 191, and filler particles 192 distributedthroughout the organic resist 191. The organic resist layer 19 is formedon the inorganic resist layer 17 by using a process such as spincoating, slit coating, dip coating, spray coating, or screen printing,for example. Among these, the spray coating is particularly preferable,because a thin organic resist layer 19 can be formed uniformly andcontinuously. The spray coater used in the spray coating method may beany kind of typical spray coater. For example, a needle-type spraycoater may be used.

The organic resist 191 is not particularly limited, and may benovolac-type resist, chemically-amplified resist, or the like, forexample. The filler particles 192 are made up of a material having adifferent etch rate than the etch rate of the organic resist 191. Inother words, in the present embodiment, the difference between the etchrate of the filler particles 192 and the etch rate of the organic resist191 is utilized to form a macro concave-convex structure 19A on thesurface of the organic resist layer 19. Herein, the etch rates of theorganic resist 191 and the filler particles 192 specifically are theetch rates with respect to a macro concave-convex structure-forming gasdescribed later.

Herein, the etch rate of the filler particles 192 is preferably higherthan the etch rate of the organic resist 191. Note that in the followingdescription, the content of the present embodiment is described underthe presupposition that the etch rate of the filler particles 192 ishigher than the etch rate of the organic resist 191. Obviously, asdescribed above, it is sufficient for the etch rate of the fillerparticles 192 to be different from the etch rate of the organic resist191. Materials selectable as the material of the filler particles 192include various types of acrylic resins, carbon particles, hollowsilica, and the like, for example.

Additionally, the average grain size of the filler particles 192 isgreater than the visible light wavelengths. Note that the average grainsize of the filler particles 192 is the value obtained by taking thearithmetic average of the sphere-equivalent diameter (distance across)of the filler particles 192, and is measurable with a device such as alaser diffraction particle size distribution measuring device, amicroscope, or a scanning electron microscope (SEM), for example.

By setting the etch rate and the average grain size of the fillerparticles 192 as above, the following advantageous effects are obtained.Namely, as described later, the organic resist layer 19 is etched by anetching gas (macro concave-convex structure-forming gas). Herein, thefiller particles 192 are etched at a higher etch rate than the organicresist 191. Consequently, as the etching of the organic resist layer 19proceeds, on the surface of the organic resist layer 19, there is formeda concave-convex structure approximately matching the shape of theinterface between the filler particles 192 and the organic resist 191disposed underneath the filler particles 192, as illustrated in FIG. 9.After that, the organic resist layer 19 is etched while maintaining thisconcave-convex structure.

Herein, since the average grain size of the filler particles 192 isgreater than the visible light wavelengths, the average cycle of theconcave-convex structure is also greater than the visible lightwavelengths. Consequently, the concave-convex structure becomes themacro concave-convex structure 19A. In other words, by setting the etchrate and the average grain size of the filler particles 192 as above,the macro concave-convex structure 19A can be formed in the organicresist layer 19.

Furthermore, by adjusting the average grain size of the filler particles192 and their concentration inside the organic resist layer 19, theaverage cycle of the macro concave-convex structure 19A may be adjustedto a desired value. For example, by increasing the average grain size ofthe filler particles 192, the average cycle can be increased. Also, byraising the concentration of the filler particles 192, the average cyclecan be decreased. In addition, by adjusting the ratio of the etch rateof the organic resist 191 and the etch rate of the filler particles 192,the arithmetic average roughness of the macro concave-convex structure19A can be adjusted to a desired value. In other words, as these etchrates become closer, the arithmetic average roughness decreases (thatis, the macro concave-convex structure 19A becomes flatter), and asthese etch rates become farther apart, the arithmetic average roughnessincreases.

The average grain size of the filler particles 192 is not particularlylimited insofar as the average grain size is within a range that isgreater than the visible light wavelengths, being preferably from 2 μmto 15 μm, and more preferably from 6 μm to 10 μm. This is because bytaking the average grain size of the filler particles 192 to be a valuewithin such a range, the anti-glare function of the optical body 4 canbe increased further, and glare in the optical body 4 can be moderated.

Also, in a case in which the average grain size of the filler particles192 is less than 2 μm, there is a possibility that the macroconcave-convex structure 12 cannot be formed on the surface of the basematerial 11. If the average grain size of the filler particles 192exceeds 15 μm, the organic resist layer 19 becomes extremely thick. Inother words, the organic resist layer 19 is required to be at least ⅓ ofthe filler particles 192. Consequently, if the average grain size of thefiller particles 192 exceeds 15 μm, the organic resist layer 19 alsobecomes extremely thick. Furthermore, if the organic resist layer 19becomes thick in this way, the etching takes large amounts of time andeffort. Additionally, if the average grain size of the filler particles192 exceeds 15 μm, there is also a possibility that the filler particles192 may sink into the organic resist layer 19 due to their own weight.If the filler particles 192 sink down, the organic resist layer 19substantially separates into an upper layer made up of the organicresist 191, and a lower layer made up of the filler particles 192. Inthis case, adjusting the arithmetic average roughness by the selectivityratio of the macro concave-convex structure-forming gas becomesextremely difficult. Although described in detail later, in the presentembodiment, the ratio of the etch rate of the organic resist 191 and theetch rate of the inorganic resist layer 17 (in other words, thedifference between the two) is utilized to adjust the arithmetic averageroughness of a macro concave-convex structure 17A of the inorganicresist layer 17. For example, in a case in which the etch rate of theorganic resist 191 is low and the etch rate of the inorganic resistlayer 17 is high, the arithmetic average roughness of the macroconcave-convex structure 17A increases. However, as described above, ifthe filler particles 192 sink down, little to none of the organic resist191 exists on the inorganic resist layer 17. Consequently, utilizing thedifference between the two etch rates becomes next to impossible. As aresult, adjustment of the arithmetic average roughness of the macroconcave-convex structure 17A becomes extremely difficult.

Additionally, the contained amount of the filler particles 192 is notparticularly limited insofar as the contained amount is within a rangewhereby the above advantageous effects are realized, but preferably isat a concentration that is at least enough for the filler particles 192to be distributed throughout the entire surface of the inorganic resistlayer 17. Specifically, the contained amount of the filler particles 192preferably is kept to within double the solid content mass of theorganic resist 191. If the contained amount of the filler particles 192is increased further, forming the organic resist layer 19 homogeneouslyon the inorganic resist layer 17 becomes difficult, and by extension,there is an increased possibility that the filler particles 192 may falloff the inorganic resist layer 17.

The thickness of the organic resist layer 19 is not particularly limitedinsofar as the thickness is at least ⅓ the average grain size of thefiller particles 192, but if more than double, for example, the fillerparticles 192 do not precipitate easily in etching, and there is apossibility of the process time becoming long. For this reason, thethickness of the organic resist layer 19 preferably is less than orequal to double the average grain size of the filler particles 192.

(Fourth Step)

In the fourth step, the organic resist layer 19, the inorganic resistlayer 17, the base material resist layer 15, and the base material 11are etched successively. Herein, the etching of the present embodimentis preferably dry etching that is vertically anisotropic. For example,reactive ion etching (RIE) is preferable. This is because with such anarrangement, the macro concave-convex structure and the microconcave-convex structure formed in each resist layer are transferred tothe other resist layers. For example, in the case of etching the organicresist layer 19 by etching having isotropy, such as wet etching, thereis a possibility of the micro concave-convex structure 13 not beingformed in the base material 11.

Also, the etching gas preferably includes one or more types of atomsselected from a group consisting of carbon atoms, fluorine atoms, oxygenatoms, and hydrogen atoms. For example, the etching gas may be afluorocarbon gas such as CHF₃, CH₂F₂, CF₄, C₂F₈, or C₃F₈, or a gasobtained by adding an additive gas such as O₂ gas, H₂ gas, or Ar gas toa fluorocarbon gas. The specific composition of the etching gas may beselected appropriately depending on the resist to be etched. Detailswill be described later.

The fourth process is divided into a first etching that transfers themacro concave-convex structure 19A formed in the organic resist layer 19to the inorganic resist layer 17, and a second etching that superimposesand forms the macro concave-convex structure 12 and the microconcave-convex structure 13 on the base material 11.

(First Etching)

In the first etching, first, the organic resist layer 19 is etched. Theetching gas used in the first etching (hereinafter also designated the“macro concave-convex structure-forming gas”) includes a first etchinggas and a second etching gas. Herein, the etch rate of the organicresist 191 with respect to the first etching gas is higher than the etchrate of the inorganic resist layer 17 with respect to the first etchinggas. Herein, the etch rate of the organic resist 191 with respect to thesecond etching gas is lower than the etch rate of the inorganic resistlayer 17 with respect to the second etching gas. The first etching gasis O₂ gas, for example, while the second etching gas is a fluorocarbongas, for example.

By etching the organic resist layer 19, as illustrated in FIG. 9, themacro concave-convex structure 19A is formed on the surface of theorganic resist layer 19. The shape of the macro concave-convex structure19A varies every time the macro concave-convex structure-forming gasetches the filler particles 192. Subsequently, the shape of the macroconcave-convex structure 19A becomes fixed when all of the fillerparticles 192 are etched. After that, the organic resist layer 19 isetched while keeping the shape of the macro concave-convex structure19A.

The first etching still continues even after the macro concave-convexstructure-forming gas reaches the inorganic resist layer 17. At thispoint, since the etching is performed by dry etching that is verticallyanisotropic, as illustrated in FIG. 10, the macro concave-convexstructure 19A is transferred to the inorganic resist layer 17. In otherwords, the macro concave-convex structure 17A is formed on the surfaceof the inorganic resist layer 17. The first etching ends when the macroconcave-convex structure 19A is entirely transferred to the inorganicresist layer 17.

At this point, the macro concave-convex structure-forming gas is amixture of the first etching gas and the second etching gas having theproperties described above. For this reason, the etch rate of theorganic resist 191 with respect to the macro concave-convexstructure-forming gas and the etch rate of the inorganic resist layer 17with respect to the macro concave-convex structure-forming gas aredifferent. In other words, the selectivity ratio of the macroconcave-convex structure-forming gas is different. At this point, theselectivity ratio of the macro concave-convex structure-forming gas isthe value obtained by dividing the etch rate of the organic resist 191with respect to the macro concave-convex structure-forming gas by theetch rate of the inorganic resist layer 17 with respect to the macroconcave-convex structure-forming gas. Consequently, the shape of themacro concave-convex structure 17A does not match the macroconcave-convex structure 19A exactly. Specifically, the arithmeticaverage roughness of the macro concave-convex structure 17A is differentfrom the arithmetic average roughness of the macro concave-convexstructure 19A.

Additionally, the arithmetic average roughness of the macroconcave-convex structure 17A is adjustable by adjusting the selectivityratio of the macro concave-convex structure-forming gas. The method ofadjusting the selectivity ratio of the macro concave-convexstructure-forming gas may be, for example, adjusting the mixture ratioof the first etching gas and the second etching gas, for example. Forexample, in the case of increasing the mixture ratio of the firstetching gas, the selectivity ratio of the macro concave-convexstructure-forming gas increases (in other words, the etch rate of theinorganic resist layer 17 decreases, while the etch rate of the organicresist 191 increases). For this reason, the arithmetic average roughnessof the macro concave-convex structure 17A decreases. In other words, themacro concave-convex structure 17A becomes shallower. On the other hand,in the case of increasing the mixture ratio of the second etching gas,the selectivity ratio of the macro concave-convex structure-forming gasdecreases (in other words, the etch rate of the inorganic resist layer17 increases, while the etch rate of the organic resist 191 decreases).For this reason, the arithmetic average roughness of the macroconcave-convex structure 17A increases. In other words, the macroconcave-convex structure 17A becomes deeper.

In this way, according to the present embodiment, by adjusting themixture ratio of the first etching gas and the second etching gas, theselectivity ratio of the macro concave-convex structure-forming gas canbe adjusted, and by extension, the arithmetic average roughness of themacro concave-convex structure 17A can be adjusted. Note that theselectivity ratio of the macro concave-convex structure-forming gas isalso adjustable by adjusting the combination of the organic resist 191and the inorganic resist constituting the inorganic resist layer 17.Also, the average cycle of the macro concave-convex structure 17Aapproximately matches the average cycle of the macro concave-convexstructure 19A. In this way, in the present embodiment, the average cycleof the macro concave-convex structure 17A can be adjusted by adjustingthe average grain size and concentration of the filler particles 192,and the arithmetic average roughness of the macro concave-convexstructure 17A can be adjusted by adjusting the selectivity ratio of themacro concave-convex structure-forming gas. Consequently, a macroconcave-convex structure 17A having the desired average cycle andarithmetic average roughness can be formed.

Note that the first etching may also be conducted repeatedly beforeconducting the second etching. By repeatedly conducting the firstetching, the average cycle of the macro concave-convex structure 17A canbe increased, and the arithmetic average roughness can be decreased.

(Second Etching)

In the second etching, first, the inorganic resist layer 17 is etched.The etching gas used in the second etching (hereinafter also designatedthe “superimposed structure-forming gas”) is not particularly limitedinsofar as the etching gas is able to etch the inorganic resist layer17, the base material resist layer 15, and the base material 11. Forexample, in the case in which the base material 11 is quartz glass, thesuperimposed structure-forming gas may be a mixture of one or multipletypes of fluorocarbon gases. Examples of fluorocarbon gases includeCHF₃, CH₂F₂, CF₄, C₂F₈, and C₃F₈. The superimposed structure-forming gasmay also be a gas obtained by adding an additive gas such as H₂ gas orAr gas to these fluorocarbon gases. Note that the superimposedstructure-forming gas may additionally include O₂ gas, but since O₂ gasis greatly isotropic compared to other gases, the concentration of O₂gas is preferably as low as possible. Note that in the first etching, O₂gas is included in the macro concave-convex structure-forming gas.However, in the first etching, only the comparatively large concavitiesand convexities of the macro concave-convex structure 17A are formed inthe inorganic resist layer 17, and thus the macro concave-convexstructure-forming gas having some degree of isotropy does not pose anyparticular problem.

The inorganic resist layer 17 is etched while keeping the shape of themacro concave-convex structure 17A. As the second etching progresses,the superimposed structure-forming gas reaches the base material resistlayer 15. After that, the inorganic resist layer 17 existing in theconcavities of the micro concave-convex structure 15B and the basematerial resist layer 15 (that is, the convexities of the microconcave-convex structure 15B) are etched by the superimposedstructure-forming gas. As the etching progresses further, thesuperimposed structure-forming gas reaches the base material 11.

Herein, in the case in which the etch rate of the base material resistlayer 15 is higher than the etch rate of the inorganic resist layer 17,the convexities of the micro concave-convex structure 15B disappearearlier than the inorganic resist layer 17 existing in the concavitiesof the micro concave-convex structure 15B. Consequently, in this case,the base material 11 is etched starting from the portions where theconvexities of the micro concave-convex structure 15B existed. As thesecond etching progresses, the inorganic resist layer 17 existing in theconcavities of the micro concave-convex structure 15B also disappearcompletely. After that, the entire surface of the base material 11 isetched. With this arrangement, a micro concave-convex structure 13having the inverse shape of the micro concave-convex structure 15B isformed on the surface of the base material 11.

On the other hand, in the case in which the etch rate of the basematerial resist layer 15 is lower than the etch rate of the inorganicresist layer 17, the inorganic resist layer 17 existing in theconcavities of the micro concave-convex structure 15B disappears earlierthan the convexities of the micro concave-convex structure 15B.Consequently, in this case, the base material 11 is etched starting fromthe portions where the concavities of the micro concave-convex structure15B existed. As the second etching progresses, the convexities of themicro concave-convex structure 15B also disappear completely. Afterthat, the entire surface of the base material 11 is etched. With thisarrangement, a micro concave-convex structure 13 having the samearrangement pattern (the arrangement pattern of concavities andconvexities) as the micro concave-convex structure 15B is formed on thesurface of the base material 11.

While the micro concave-convex structure 13 is formed on the surface ofthe base material 11, the macro concave-convex structure 17A of theinorganic resist layer 17 is also transferred to the base material 11.The second etching ends when the macro concave-convex structure 17A isentirely transferred to the base material 11. With the above steps, themacro concave-convex structure 12 and the micro concave-convex structure13 are formed superimposed onto the surface of the base material 11. Inother words, the master 1 is produced.

Herein, in the case in which the inorganic resist constituting theinorganic resist layer 17 and the material of the base material 11match, the shape of the macro concave-convex structure 12 approximatelymatches the macro concave-convex structure 17A. However, in the case inwhich the inorganic resist constituting the inorganic resist layer 17and the material of the base material 11 are different, the etch rate ofthe inorganic resist layer 17 with respect to the superimposedstructure-forming gas and the etch rate of the base material 11 withrespect to the superimposed structure-forming gas are different. Inother words, the selectivity ratio of the superimposed structure-forminggas is different. At this point, the selectivity ratio of thesuperimposed structure-forming gas is the value obtained by dividing theetch rate of the inorganic resist layer 17 with respect to thesuperimposed structure-forming gas by the etch rate of the base material11 with respect to the superimposed structure-forming gas. Consequently,the shape of the macro concave-convex structure 12 does not match themacro concave-convex structure 17A exactly. Specifically, the arithmeticaverage roughness of the macro concave-convex structure 12 is differentfrom the arithmetic average roughness of the macro concave-convexstructure 17A.

Additionally, the arithmetic average roughness of the macroconcave-convex structure 12 is adjustable by modifying the selectivityratio of the superimposed structure-forming gas. The method of modifyingthe selectivity ratio of the superimposed structure-forming gas may be,for example, modifying the combination of the inorganic resistconstituting the inorganic resist layer 17 and the material of the basematerial 11.

Additionally, in the case of increasing the selectivity ratio of thesuperimposed structure-forming gas, the etch rate of the inorganicresist layer 17 increases while the etch rate of the base material 11decreases, and thus the arithmetic average roughness of the macroconcave-convex structure 12 decreases. In other words, the macroconcave-convex structure 12 becomes shallower. On the other hand, in thecase of decreasing the selectivity ratio of the superimposedstructure-forming gas, the etch rate of the inorganic resist layer 17decreases while the etch rate of the base material 11 increases, andthus the arithmetic average roughness of the macro concave-convexstructure 12 increases. In other words, the macro concave-convexstructure 12 becomes deeper.

In this way, according to the present embodiment, by modifying thecombination of the inorganic resist constituting the inorganic resistlayer 17 and the material of the base material 11, the selectivity ratioof the superimposed structure-forming gas can be adjusted, and byextension, the arithmetic average roughness of the macro concave-convexstructure 12 can be adjusted. For this reason, in the case in which thearithmetic average roughness of the macro concave-convex structure 17Aformed in the inorganic resist layer 17 is different from the desiredvalue, for example, by further adjusting the selectivity ratio of thesuperimposed structure-forming gas, the arithmetic average roughness ofthe macro concave-convex structure 12 can be set to the desired value.Note that the average cycle of the macro concave-convex structure 12approximately matches the average cycle of the macro concave-convexstructure 17A.

Consequently, according to the present embodiment, the average cycle ofthe macro concave-convex structure 12 can be adjusted by adjusting theaverage grain size and concentration of the filler particles 192, andthe arithmetic average roughness of the macro concave-convex structure12 can be adjusted by adjusting the selectivity ratio of the macroconcave-convex structure-forming gas and the selectivity ratio of thesuperimposed structure-forming gas. Consequently, a macro concave-convexstructure 12 having the desired average cycle and arithmetic averageroughness can be formed.

[1.2.1. First Modification of Master Manufacturing Method]

Next, a first modification of the master manufacturing method will bedescribed with reference to FIG. 11. As illustrated in FIG. 11, in thefirst modification, the inorganic resist layer 17 is taken to have atwo-layer structure. In other words, in the first modification, theinorganic resist layer 17 is made up of a first inorganic resist layer171 formed on the micro concave-convex structure 15B, and a secondinorganic resist layer 172 formed on the first inorganic resist layer171. Each of the inorganic resist layers 171 and 172 is formed by amethod similar to the second step described above.

The inorganic resist constituting the first inorganic resist layer 171and the second inorganic resist layer 172 may be, for example, SiO₂, Si,diamond-like carbon (DLC), W, Mo, or a metallic oxide including one ormultiple types of transition metals such as W and Mo. Herein, the firstinorganic resist layer 171 and the second inorganic resist layer 172 aremade up of different inorganic resists (specifically, the etch rates aredifferent). Furthermore, the etch rate of the second inorganic resistlayer 172 is different from the etch rate of the base material resistlayer 15. The other steps are all the same as the steps describedearlier.

With the first modification, the following advantageous effects areobtained. Namely, as described above, the arithmetic average roughnessof the macro concave-convex structure 17A can be adjusted by adjustingthe selectivity ratio of the macro concave-convex structure-forming gas.Additionally, the selectivity ratio of the macro concave-convexstructure-forming gas can also be adjusted by the combination of theorganic resist and the inorganic resist constituting the inorganicresist layer 17. Consequently, in the case in which the inorganic resistlayer 17 and the base material resist layer 15 are made up of the sameinorganic resist, the arithmetic average roughness of the macroconcave-convex structure 17A becomes the desired value in some cases.However, if the inorganic resist layer 17 is taken to have a singlelayer, and is also formed from the same inorganic resist as the basematerial resist layer 15, the micro concave-convex structure 13 cannotbe formed.

Meanwhile, the selectivity ratio of the macro concave-convexstructure-forming gas is determined by the combination of the organicresist, and the inorganic resist in the portion of the inorganic resistlayer 17 that contacts the organic resist layer 19.

Consequently, in the first modification, the portion that contacts theorganic resist layer 19, namely the second inorganic resist layer 172,can be formed from an inorganic resist that is the same as the basematerial resist layer 15, while the first inorganic resist layer 171 canbe formed from an inorganic resist that is different from the basematerial resist layer 15. In other words, according to the firstmodification, the choice of materials for the second inorganic resistlayer 172 can be increased.

Note that the thickness ratio of the first inorganic resist layer 171and the second inorganic resist layer 172 is not particularly limited,and may be set in accordance with the etch rates of the first inorganicresist layer 171 and the second inorganic resist layer 172. For example,it is sufficient to set the thickness of a layer with a fast etch ratein proportion with the etch rate ratio with respect to a layer with aslow etch rate.

[1.2.2. Second Modification of Master Manufacturing Method]

Next, a second modification of the master manufacturing method will bedescribed with reference to FIGS. 4 to 6 and FIG. 12. In the secondmodification, the first step and the second step are different.

In the first step, as illustrated in FIGS. 4 to 6, the base materialresist layer 15 is formed on the base material 11, and the microconcave-convex structure 15B (third micro concave-convex structure) isformed in the base material resist layer 15. Subsequently, the basematerial resist layer 15 and the base material 11 are etched by a methodsimilar to the second etching described above. With this arrangement,the micro concave-convex structure 14 (first micro concave-convexstructure) illustrated in FIG. 12 is formed on the surface of the basematerial 11. Consequently, in the second modification, the base material11 constitutes a base material body. The micro concave-convex structure14 has the same arrangement pattern (the arrangement pattern ofconcavities and convexities) as the micro concave-convex structure 15B.

In the second step, similarly to the first modification, an inorganicresist layer 17 with a two-layer structure is formed on the microconcave-convex structure 14. At this point, the first inorganic resistlayer 171 is a resist layer for forming the micro concave-convexstructure 13 in the base material 11, and is made of DLC. The secondinorganic resist layer 172 is made of an inorganic resist similar to thefirst modification (excluding DLC). After that, processes similar to theprocesses described above are conducted.

<2. Configuration of Exposure Device>

Next, the configuration of the exposure device 200 will be describedbased on FIG. 13. The exposure device 200 is a device that exposes thebase material resist layer 15. The exposure device 200 is provided witha laser light source 201, a first mirror 203, a photodiode (PD) 205, adeflecting optical system, a control mechanism 230, a second mirror 213,a movable optical table 220, a spindle motor 225, and a turntable 227.Also, the base material 11 is placed on the turntable 227 and able to berotated.

The laser light source 201 is a light source that emits laser light 20,and is a device such as a solid-state laser or a semiconductor laser,for example. The wavelength of the laser light 20 emitted by the laserlight source 201 is not particularly limited, but may be a wavelength inthe blue light band from 400 nm to 500 nm, for example. Also, it issufficient for the spot diameter of the laser light 20 (the diameter ofthe spot radiated onto the resist layer) to be smaller than the diameterof the open face of a concavity of the micro concave-convex structure15B, such as approximately 200 nm, for example. The laser light 20emitted from the laser light source 201 is controlled by the controlmechanism 230.

The laser light 20 emitted from the laser light source 201 advancesdirectly in a collimated beam, reflects off the first mirror 203, and isguided to the deflecting optical system.

The first mirror 203 is made up of a polarizing beam splitter, and has afunction of reflecting one polarized component, and transmitting theother polarized component. The polarized component transmitted throughthe first mirror 203 is sensed by the photodiode 205 andphotoelectrically converted. Also, the photodetection signalphotoelectrically converted by the photodiode 205 is input into thelaser light source 201, and the laser light source 201 conducts phasemodulation of the laser light 20 based on the input photodetectionsignal.

In addition, the deflecting optical system is provided with a condenserlens 207, an electro-optic deflector (EOD) 209, and a collimator lens211.

In the deflecting optical system, the laser light 20 is condensed ontothe electro-optic deflector 209 by the condenser lens 207. Theelectro-optic deflector 209 is an element capable of controlling theradiation position of the laser light 20. With the electro-opticdeflector 209, the exposure device 200 is also able to vary theradiation position of the laser light 20 guided onto the movable opticaltable 220. After the radiation position is adjusted by the electro-opticdeflector 209, the laser light 20 is converted back into a collimatedbeam by the collimator lens 211. The laser light 20 exiting thedeflecting optical system is reflected by the second mirror 213, andguided level with and parallel to the movable optical table 220.

The movable optical table 220 is provided with a beam expander (BEX) 221and an objective lens 223. The laser light 20 guided to the movableoptical table 220 is shaped into a desired beam shape by the beamexpander 221, and then radiated via the objective lens 223 onto the basematerial resist layer 15 formed on the base material 11. In addition,the movable optical table 220 moves by one feed pitch (track pitch) inthe direction of the arrow R (feed pitch direction) every time the basematerial 11 undergoes one rotation. The base material 11 is placed onthe turntable 227. The spindle motor 225 causes the turntable 227 torotate, thereby causing the base material 11 to rotate.

In addition, the control mechanism 230 is provided with a formatter 231and a driver 233, and controls the radiation of the laser light 20. Theformatter 231 generates a modulation signal that controls the radiationof the laser light 20, and the driver 233 controls the laser lightsource 201 based on the modulation signal generated by the formatter231. As a result, the irradiation of the base material 11 by the laserlight 20 is controlled.

The formatter 231 generates a control signal for irradiating the basematerial resist layer 15 with the laser light 20, based on an inputimage depicting an arbitrary pattern to draw on the base material resistlayer 15. Specifically, first, the formatter 231 acquires an input imagedepicting an arbitrary pattern to draw on the base material resist layer15. The input image is an image corresponding to a development of theouter circumferential surface of the base material resist layer 15, inwhich the outer circumferential surface of the base material resistlayer 15 is cut in the axial direction and expanded in a single plane.Next, the formatter 231 partitions the input image into sub-regions of acertain size (for example, partitions the input image into a lattice),and determines whether or not the draw pattern is included in each ofthe sub-regions. Subsequently, the formatter 231 generates a controlsignal to perform control to irradiate with the laser light 20 eachsub-region determined to include the draw pattern. Furthermore, thedriver 233 controls the output of the laser light source 201 based onthe control signal generated by the formatter 231. As a result, theirradiation of the base material resist layer 15 by the laser light 20is controlled.

<3. Method of Manufacturing Optical Body Using Master>

Next, an example of a method of manufacturing the optical body 4 usingthe master 1 will be described with reference to FIG. 14. The opticalbody 4 can be manufactured by a roll-to-roll transfer device 300 usingthe master 1. In the transfer device 300 illustrated in FIG. 14, theoptical body 4 is produced using a light-curing resin.

The transfer device 300 is provided with the master 1, a base materialsupply roll 301, a take-up roll 302, guide rolls 303 and 304, a nip roll305, a separation roll 306, an applicator device 307, and a light source309.

The base material supply roll 301 is a roll around which a long-lengthbase material film 3 is wound in a roll, while the take-up roll 302 is aroll that takes up the optical body 4. Also, the guide rolls 303 and 304are rolls that transport the base material film 3. The nip roll 305 is aroll that puts the base material film 3 laminated with an uncured resinlayer 310, or in other words a transfer film 3 a, in close contact withthe master 1. The separation roll 306 is a roll that separates the basematerial film 3 laminated with a cured resin layer 310 a, or in otherwords the optical body 4, from the master 1.

The applicator device 307 is provided with an applicating means such asa coater, and applies an uncured light-curing resin composition to thebase material film 3, and forms the uncured resin layer 310. Theapplicator device 307 may be a device such as a gravure coater, a wirebar coater, or a die coater, for example. Also, the light source 309 isa light source that emits light of a wavelength able to cure thelight-curing resin composition, and may be a device such as anultraviolet lamp, for example.

The light-curing resin composition is a resin that decreases in fluidityand cures by being irradiated with light of a predetermined wavelength.Specifically, the light-curing resin composition may be an ultravioletcurable resin such as an acrylic resin. The light-curing resincomposition may contain an initiator, a filler, a functional additive, asolvent, an inorganic material, a pigment, an antistatic agent, asensitizing dye, etc., as necessary.

In the transfer device 300, first, the base material film 3 is sentcontinuously from the base material supply roll 301 via the guide roll303. Note that partway through the delivery, the base material supplyroll 301 may also be changed to a base material supply roll 301 of aseparate lot. The uncured light-curing resin composition is applied bythe applicator device 307 to the delivered base material film 3, and theuncured resin layer 310 is laminated onto the base material film 3. As aresult, the transfer film 3 a is prepared. The transfer film 3 a is putinto close contact with the master 1 by the nip roll 305. The lightsource 309 irradiates with light the uncured resin layer 310 put inclose contact with the master 1, thereby curing the uncured resin layer310. With this arrangement, the arrangement pattern of the macroconcave-convex structure 12 and the micro concave-convex structure 13formed on the outer circumferential face of the master 1 is transferredto the uncured resin layer 310. In other words, there is formed thecured resin layer 310 a, on which is formed the inverse pattern of themacro concave-convex structure 12 and the micro concave-convex structure13. At this point, the light source 309 may also radiate light obliquelywith respect to concavities 422 of the micro concave-convex structure 42(see FIG. 15). In this case, only a part of the concavities 422 iscured. Next, the base material film 3 on which is laminated the curedresin layer 310 a, or in other words the optical body 4, is separatedfrom the master 1 by the separation roll 306. Next, the optical body 4is taken up by the take-up roll 302 via the guide roll 304.

In this way, in the transfer device 300, the circumferential shape ofthe master 1 is transferred to the transfer film 3 a while transportingthe transfer film 3 a roll-to-roll. With this arrangement, the opticalbody 4 is produced.

Note that in the case of producing the optical body 4 with athermoplastic resin, the applicator device 307 and the light source 309become unnecessary. Also, the base material film 3 is taken to be athermoplastic resin film, and a heater device is disposed fartherupstream than the master 1. The base material film 3 is heated andsoftened by the heater device, and after that, the base material film 3is pressed against the master 1. With this arrangement, the arrangementpattern of the macro concave-convex structure 12 and the microconcave-convex structure 13 formed on the circumferential surface of themaster 1 is transferred to the base material film 3. Note that the basematerial film 3 may also be taken to be a film made up of a resin otherthan a thermoplastic resin, and the base material film 3 and athermoplastic resin film may be laminated. In this case, the laminatedfilm is pressed against the master 1 after being heated by the heaterdevice.

Consequently, the transfer device 300 is able to continuously produce atransfer product to which has been transferred the arrangement patternof the macro concave-convex structure 12 and the micro concave-convexstructure 13 formed in the master 1, or in other words, the optical body4. Herein, the macro concave-convex structure 12 formed on thecircumferential face of the master 1 has the desired average cycle andarithmetic average roughness. Consequently, the macro concave-convexstructure 41 formed in the optical body 4 (see FIG. 15) has the desiredaverage cycle and arithmetic average roughness.

<4. Structure of Optical Body>

[4-1. Overall Configuration of Optical Body]

FIG. 15 illustrates the configuration of the optical body 4 produced bythe above manufacturing method. The optical body 4 is film-shaped, forexample, and is provided with a macro concave-convex structure 41 formedon the surface thereof, and a micro concave-convex structure 42superimposed onto the macro concave-convex structure 41.

The macro concave-convex structure 41 has convexities 411 andconcavities 412. The shape of the macro concave-convex structure 41 isthe inverse shape of the macro concave-convex structure 12 of the master1. The micro concave-convex structure 42 has convexities 421 andconcavities 422. The shape of the micro concave-convex structure 42 isthe inverse shape of the micro concave-convex structure 13 of the master1. Furthermore, the optical body 4 according to the present embodimentis able to realize a high anti-glare function with the macroconcave-convex structure 41, and a high anti-reflection function withthe micro concave-convex structure 42. Consequently, it is not necessaryto mix into the optical body 4 a separate scatterer in order to improvethe anti-glare function of the optical body 4. Consequently, accordingto the present embodiment, an optical body 4 having a high anti-glarefunction and a high anti-reflection function can be producedconsistently and at low cost.

[4.2. Average Cycle and Arithmetic Average Roughness of Optical Body]

The arithmetic average roughness of the optical body 4 is the arithmeticaverage roughness of the superimposed structure of the macroconcave-convex structure 41 and the micro concave-convex structure 42.Herein, in the present embodiment, the arithmetic average roughness ofthe macro concave-convex structure 41 approximately matches thearithmetic average roughness of the macro concave-convex structure 12 ofthe master 1. Additionally, in the present embodiment, when producingthe master 1, it is possible to keep the arrangement pattern of themicro concave-convex structure 13 fixed while arbitrarily varying onlythe shape of the macro concave-convex structure 12. Consequently, in thepresent embodiment, it is possible to produce a variety of opticalbodies 4 with a different arithmetic average roughness of thesuperimposed structure while the arrangement pattern of the microconcave-convex structure 42 remains fixed. Hereinafter, unlessspecifically noted otherwise, the “arithmetic average roughness of theoptical body 4” is taken to mean the “arithmetic average roughness ofthe superimposed structure of the optical body 4”. Meanwhile, theaverage cycle of the optical body 4 is the average cycle of the macroconcave-convex structure 41.

<5. Relationship Between Average Cycle and Arithmetic Average Roughness,and Haze Value of Optical Body>

As described above, according to the present embodiment, the averagecycle and the arithmetic average roughness of the optical body 4 can beset to desired values. Additionally, after a detailed investigation ofthe average cycle and the arithmetic average roughness of the opticalbody 4, the inventors discovered that there is a tight correlationbetween these values and the haze value of the optical body 4. Anexample of the correlation between the average cycle and arithmeticaverage roughness of the optical body 4 and the haze value of theoptical body 4 is illustrated in FIG. 16. The horizontal axis in FIG. 16expresses a value (=Ra/Rsm) obtained by dividing the arithmetic averageroughness (=Ra) by the average cycle (=Rsm) of the optical body 4. Thevertical axis expresses the haze value (%) of the optical body 4.

The points A indicate correlations between Ra/Rsm and the haze value.Note that the correlations indicated by the points A are the onesobtained by the examples to be described later. As FIG. 16 clearlydemonstrates, as Ra/Rsm increases, the haze value also increases. Alsodemonstrated is that the amount of increase in the haze value per unitincrease in Ra/Rsm becomes greater as Ra/Rsm becomes smaller.Consequently, according to the present embodiment, an optical body 4having the desired haze value can be produced consistently.Particularly, in the related art, an optical body with a high haze valuecould not be produced consistently. In other words, even with thetechnology of the related art, an optical body with a high haze valuecould be produced by polishing the optical body. However, the qualityfluctuations were severe, and did not stand up to practical use. In thepresent embodiment, an optical body with a haze value can be producedconsistently.

<6. Exemplary Applications of Optical Body>

The optical body 4 produced by the present embodiment is applicable to avariety of uses. For example, the optical body 4 can be used as ananti-reflection film and an anti-glare film for display devices, opticalelements, and the like. The optical body 4 is not limited to these uses,and is applicable to any field demanding anti-reflection and anti-glare.

EXAMPLES

Hereinafter, the master 1 and the optical body 4 according to theforegoing embodiment will be described specifically with reference toexamples and comparative examples. Note that the examples indicatedbelow are conditional examples for indicating the embodimentpossibilities and advantageous effects of the master 1 and the opticalbody 4 according to the foregoing embodiment, and a master 1 and opticalbody 4 of the present invention are not limited to the examples below.

[1. Manufacture of Optical Body]

The optical body 4 was manufactured according to the following steps.

Example 1

A base material 11 made of silica glass in a hollow round cylindricalshape was prepared, and a base material resist layer 15 made of tungstenoxide was formed on the surface of the base material 11 by sputtering.The base material resist layer 15 was taken to be 50 nm thick. Next, byirradiating the base material resist layer with laser light from theexposure device 200 illustrated in FIG. 13, a latent image 15A of thestaggered arrangement pattern was formed in the base material resistlayer 15. At this point, the set values in the exposure device 200related to the pitch of the latent image 15A were taken to be a dotpitch of 230 nm and a track pitch of 153 nm.

Next, by dripping an alkaline developing solution (NMD-3 by Tokyo OhkaKogyo Co., Ltd.) onto the base material resist layer 15, the exposedpart (the portion where the latent image 15A is formed) was removed. Inother words, a development process was conducted. With this arrangement,the micro concave-convex structure 15B was formed in the base materialresist layer 15.

Next, an inorganic resist layer 17 made of SiO₂ was formed on the microconcave-convex structure 15B by sputtering. Herein, the inorganic resistlayer 17 is taken to be a single layer, with a thickness of 1000 nm.Also, the etch rate of the inorganic resist layer 17 with respect to thesuperimposed structure-forming gas (the composition of which will bedescribed later) was different from the etch rate of the base materialresist layer 15 with respect to the superimposed structure-forming gas.Specifically, the ratio of the etch rate of the base material resistlayer 15 to the etch rate of the inorganic resist layer 17 was ⅓. Notethat the etch rates of both were measured by etching a single layer ofthe inorganic resist layer 17 and a single layer of the base materialresist layer 15 under the conditions of the second etching to bedescribed later.

Next, P4210 by AZ Electronic Materials was prepared as the organicresist 191, and acrylic particles (SE010T by Negami Chemical IndustrialCo., Ltd.) were prepared as the filler particles 192. At this point,when the average grain size of the acrylic particles were measured witha microscope, the average grain size was 10 μm.

Subsequently, by mixing the organic resist 191 and the filler particles192 at a weight ratio of 70:30, an organic resist composition wasproduced. Subsequently, by mixing this organic resist composition withthe solvent PGM (propylene glycol monomethyl ether) at a weight ratio of1:20, a spray coating dispersion fluid was produced.

Next, by spraying the spray coating dispersion fluid onto the inorganicresist layer 17, an organic resist layer 19 from 10 μm to 15 μm thickwas formed. In this way, the thickness of the organic resist layer 19takes various values on the surface of the organic resist layer 19, butthe thickness always takes a value within the above range. In otherwords, in Example 1, the organic resist layer 19 was formed on theinorganic resist layer 17 by spray coating. Note that the solvent PGMvolatilizes while being sprayed and also when left out in open air.

Next, a reactive ion etching device was used to conduct the firstetching. The macro concave-convex structure-forming gas used in thefirst etching was a gas obtained by mixing CF₄ gas and O₂ gas at a flowratio (sccm ratio) of 2:28. Also, the output of the reactive ion etchingdevice was taken to be 200 W, and the gas pressure was taken to be 0.5Pa.

Note that when etching was interrupted during the etching of the organicresist layer 19, and the surface of the organic resist layer 19 wasobserved with an SEM and a microscope, it was confirmed that the macroconcave-convex structure 19A was formed on the surface of the organicresist layer 19. Also, from the shape of the macro concave-convexstructure 19A (particularly, the depth of the concavities), the ratio ofthe etch rate of the organic resist with respect to the macroconcave-convex structure-forming gas and the etch rate of the fillerparticles 192 with respect to macro concave-convex structure-forming gaswas estimated. As a result, the ratio of the etch rates was ½.

Also, the selectivity ratio of the macro concave-convexstructure-forming gas was 25/1. Note that the selectivity ratio wascomputed according to the following method. Namely, a single layer ofthe organic resist 191 and a single layer of SiO₂ were etched under theabove etching conditions, and the etch rates of both were measured.Subsequently, the selectivity ratio was computed by dividing the etchrate of the organic resist 191 by the etch rate of the inorganic resistlayer 17.

Subsequently, when the organic resist layer 19 disappeared completely(that is, when the macro concave-convex structure 19A of the organicresist layer 19 was entirely transferred to the inorganic resist layer17), the first etching was ended. After that, when the surface of theinorganic resist layer 17 was observed with an SEM, it was confirmedthat the macro concave-convex structure 17A was formed on the surface ofthe inorganic resist layer 17.

Next, a reactive ion etching device was used to conduct the secondetching. The superimposed structure-forming gas used in the secondetching was a gas obtained by mixing CHF₃ gas and CF₄ gas at a flowratio (sccm ratio) of 27:3. Also, the output of the reactive ion etchingdevice was taken to be 200 W, the gas pressure was taken to be 0.5 Pa,and the etching time was taken to be 2 hours. By the above steps, themaster 1 according to Example 1 was produced.

Herein, the selectivity ratio of the superimposed structure-forming gaswas ⅓. Note that the selectivity ratio was computed according to thefollowing method. Namely, the base material 11 and a single layer ofSiO₂ were etched under the above etching conditions, and the etch ratesof both were measured. Subsequently, the selectivity ratio was computedby dividing the etch rate of the organic resist 191 by the etch rate ofthe inorganic resist layer 17.

Next, the transfer device 300 illustrated in FIG. 14 was used to producethe optical body 4. Note that the base material film 3 was taken to bepolyethylene terephthalate film, and the light-curing resin compositionwas taken to be acrylic resin acrylate. Also, the uncured resin layer310 was cured by irradiating the uncured resin layer 310 withultraviolet rays at 1000 mJ/cm². By the above steps, the optical body 4was produced. Subsequently, the Surfcorder ET200 by Kosaka LaboratoryLtd. was used to measure the arithmetic average roughness and theaverage cycle of the optical body 4. Herein, the measurement conditionswere set to a speed of 100 μm/s and a measurement strength of 100 μN. Asa result, the arithmetic average roughness (=Ra) was 0.151 μm, and theaverage cycle (=Rsm) was 10.39 μm. Consequently, Ra/Rsm was 0.014. Also,the dot pitch of the micro concave-convex structure 42 of the opticalbody 4 was 270 nm, the track pitch was 153 nm, and the depth (the heightof the convexities 421 and the depth of the concavities 422) wasapproximately from 500 nm to 600 nm. These values were confirmed with anSEM and a cross-section transmission electron microscope (TEM).

Example 2

Other than conducting the first etching twice before conducting thesecond etching, a process similar to Example 1 was conducted. Note thatthe second round of the first etching was conducted under the sameconditions of the first round of the first etching. For example, thespray coating dispersion fluid was sprayed onto the inorganic resistlayer 17 under the same spraying conditions (such as the spray pressureand the spray time) as the first round of the first etching. When thearithmetic average roughness and the average cycle of the optical body 4were measured by a method similar to Example 1, the arithmetic averageroughness was 0.112 μm, and the average cycle was 11.8 μm. Consequently,Ra/Rsm was 0.009. Also, it was demonstrated that by repeatedlyconducting the first etching, the average cycle of the optical body 4can be increased, and the arithmetic average roughness can be decreased.Consequently, by repeatedly conducting the first etching, the averagecycle of the macro concave-convex structure 17A can be increased, andthe arithmetic average roughness can be decreased. Also, the dot pitch,track pitch, and depth of the micro concave-convex structure 42 of theoptical body 4 were on a comparable level to Example 1. These valueswere confirmed with an SEM.

Example 3

In Example 3, the average grain size of the filler particles 192 wastaken to be 6 μm, the inorganic resist layer 17 was given a two-layerstructure, and the composition of the macro concave-convexstructure-forming gas was changed. Otherwise, a process similar toExample 1 was conducted. Specifically, in Example 3, a first inorganicresist layer 171 made of Sift was formed on the micro concave-convexstructure 15B by sputtering. The first inorganic resist layer 171 wastaken to be 200 nm thick. Next, a second inorganic resist layer 172 madeof tungsten oxide was formed on the first inorganic resist layer 171 bysputtering. The second inorganic resist layer 172 was taken to be 500 nmthick. Consequently, Example 3 corresponds to the first modification.

Next, other than using acrylic particles with an average grain size of 6μm (SE006T by Negami Chemical Industrial Co., Ltd.), a spray coatingdispersion fluid was produced according to a method similar toExample 1. Next, by spraying the spray coating dispersion fluid onto thesecond inorganic resist layer 172 according to a method similar toExample 1, the organic resist layer 19 was formed on the secondinorganic resist layer 172.

Next, the first etching and the second etching were conducted accordingto methods similar to Example 1. However, the macro concave-convexstructure-forming gas was a gas obtained by mixing CF₄ gas and O₂ gas ata flow ratio (sccm ratio) of 5:25. When the arithmetic average roughnessand the average cycle of the macro concave-convex structure 41 formed inthe optical body 4 was measured according to a method similar to Example1, the arithmetic average roughness was 0.311 μm, and the average cyclewas 6.69 μm. Consequently, Ra/Rsm was 0.046. Also, the dot pitch, trackpitch, and depth of the micro concave-convex structure 42 of the opticalbody 4 were on a comparable level to Example 1. These values wereconfirmed with an SEM.

Example 4

In Example 4, the optical body 4 was produced by conducting thefollowing process. Namely, first, the micro concave-convex structure 15Bwas formed on the base material 11 by a process similar to Example 1.Next, a reactive ion etching device was used to etch the base materialresist layer 15 and the base material 11. At this point, the etching gaswas a gas obtained by mixing CHF₃ gas and CF₄ gas at a flow ratio (sccmratio) of 27:3. Also, the output of the reactive ion etching device wastaken to be 150 W, the gas pressure was taken to be 0.5 Pa, and theetching time was taken to be 1 hour. By the above steps, the microconcave-convex structure 14 was formed in the base material 11.

Next, a first inorganic resist layer 171 made of DLC was formed by CVDonto the micro concave-convex structure 14. The first inorganic resistlayer 171 was taken to be 150 nm thick. Next, a second inorganic resistlayer 172 made of tungsten oxide was formed on the first inorganicresist layer 171 by sputtering. The second inorganic resist layer 172was taken to be 800 nm thick. At this point, the ratio of the etch rateof DLC with respect to the superimposed structure-forming gas and theetch rate of the base material 11 with respect to the superimposedstructure-forming gas was ⅓. Note that these etch rates are valuesmeasured by a method similar to the method described above.

Next, the organic resist layer 19 was formed on the second inorganicresist layer 172 by a method similar to Example 1. After that, byconducting processes similar to Example 1, the optical body 4 wasproduced. When the arithmetic average roughness and the average cycle ofthe optical body 4 were measured by a method similar to Example 1, thearithmetic average roughness was from 0.12 μm to 0.15 μm, and theaverage cycle was from 11 μm to 15 μm. Note that in Example 4, there wassome slight variation in the values of the arithmetic average roughnessand the average cycle depending on the measurement position of theoptical body 4. Also, the dot pitch, track pitch, and depth of the microconcave-convex structure 42 of the optical body 4 were on a comparablelevel to Example 1. These values were confirmed with an SEM.

[2. Evaluation Results of Optical Body]

(Relationship Between Arithmetic Average Roughness and Average Cycle,and Haze Value of Optical Body)

The haze values of the optical bodies 4 produced in the respectiveexamples above were measured using the Haze Meter HM-150 by MurakamiColor Research Laboratory Co., Ltd. Subsequently, points indicatingcombinations of Ra/Rsm and the haze value were plotted on an xy planewith Ra/Rsm as the horizontal axis and the haze value (%) as thevertical axis. The results are illustrated in FIG. 16. The points A inFIG. 16 indicate correlations between Ra/Rsm and the haze value.

As FIG. 16 clearly demonstrates, as Ra/Rsm increases, the haze valuealso increases. Also demonstrated is that the amount of increase in thehaze value per unit increase in Ra/Rsm becomes greater as Ra/Rsm becomessmaller.

(Observation Results of Optical Body with Electron Microscope)

First, the surface structure of the optical body 4 produced in Example 2was observed with an SEM. The results are illustrated in FIGS. 17A to17C. The magnification in FIG. 17A is 500×, while the magnification inFIG. 17B is 5000×, and the magnification in FIG. 17C is 20000×. FIG. 17Ademonstrates that the macro concave-convex structure 12 is formed on thebase material 11. Note that the approximately circular structuresdistributed throughout FIG. 17A are the macro concave-convex structure12. Also, although extremely minute in FIG. 17B, the formation of themicro concave-convex structure 13 on the same face as the macroconcave-convex structure 12 was confirmed. In FIG. 17C, the formation ofthe micro concave-convex structure 13 on the same face as the macroconcave-convex structure 12 was confirmed more clearly.

(Evaluation of Anti-Reflection Function of Optical Body)

To evaluate the anti-reflection function of the optical body 4 producedin each example, the diffuse reflection spectrum of the optical body 4was measured. First, the optical system used to measure the diffusereflection spectrum will be described on the basis of FIG. 18. In themeasurement of the diffuse reflection spectrum, light 72A from a lightsource 71 is reflected by a spherical mirror 73, and then radiated ontoa sample 77 provided inside an integrating sphere 75. Reflected light72B from the sample 77 is homogenized by being reflected multiply insidethe integrating sphere 75, and then is detected. Specifically, themeasurement of the diffuse reflection spectrum was conducted using theV-550 spectrophotometer and the absolute reflectance measuring unitARV474S by JASCO Corporation. The diffuse reflection spectra areillustrated in FIG. 19. Note that in Example 4, a spectrum comparable toExamples 1 and 2 was obtained. As FIG. 19 clearly demonstrates, theoptical bodies according to Examples 1 to 4 have low diffuse reflectancethroughout the entire visible light band, and are capable of preventingdiffuse reflection sufficiently. In this way, in the examples, even forhigh haze values of approximately 20% or greater, the diffusereflectance can be kept to 2% or less.

Also, in Example 3, the haze value has a low diffuse reflectancethroughout the visible light band compared to the other examples. Sincethe macro concave-convex structure 12 of Example 3 has a large heightdifference in the respective concavities and convexities (that is, thearithmetic average roughness Ra is large) compared to the macroconcave-convex structure 12 of the other Examples 1 and 2, when formingthe micro concave-convex structure 13, the state of etching is partlydifferent. Consequently, the micro concave-convex structure 13 has ashape that is partly different depending on the shape of the macroconcave-convex structure 12. For this reason, in Example 3, it isinferred that reflections can be suppressed over a wider range ofwavelengths.

The preferred embodiment(s) of the present invention has/have beendescribed above with reference to the accompanying drawings, whilst thepresent invention is not limited to the above examples. A person skilledin the art may find various alterations and modifications within thescope of the appended claims, and it should be understood that they willnaturally come under the technical scope of the present invention.

REFERENCE SIGNS LIST

-   1 master-   4 optical body-   41 macro concave-convex structure-   411 convexity-   412 concavity-   42 micro concave-convex structure-   421 convexity-   422 concavity-   11 base material-   12 macro concave-convex structure-   121 convexity-   122 concavity-   13 micro concave-convex structure-   131 convexity-   132 concavity-   14 micro concave-convex structure-   15 base material resist layer-   15B micro concave-convex structure-   17 inorganic resist layer-   171 first inorganic resist layer-   172 second inorganic resist layer-   19 organic resist layer-   191 organic resist-   192 filler particles

The invention claimed is:
 1. A master comprising: a first microconcave-convex structure, in which an average cycle of concavities andconvexities is less than or equal to visible light wavelengths, formedon a surface of a base material body that includes at least a basematerial; an inorganic resist layer formed on the first microconcave-convex structure; and an organic resist layer formed on theinorganic resist layer and including an organic resist and fillerparticles distributed throughout the organic resist, wherein the organicresist layer and the inorganic resist layer are etched to superimposeand form on the surface of the base material a macro concave-convexstructure in which the average cycle of concavities and convexities isgreater than visible light wavelengths, and a second microconcave-convex structure in which the average cycle of concavities andconvexities is less than or equal to visible light wavelengths, anaverage grain size of the filler particles is greater than visible lightwavelengths, and the master is manufactured by a master manufacturingmethod, the master manufacturing method comprising: a first step offorming the first micro concave-convex structure on the surface of thebase material body; a second step of forming the inorganic resist layeron the first micro concave-convex structure; a third step of forming, onthe inorganic resist layer, the organic resist layer including theorganic resist and filler particles distributed throughout the organicresist; and a fourth step of etching the organic resist layer and theinorganic resist layer to thereby superimpose and form on the surface ofthe base material the macro concave-convex structure in which theaverage cycle of concavities and convexities is greater than visiblelight wavelengths, and the second micro concave-convex structure inwhich the average cycle of concavities and convexities is less than orequal to visible light wavelengths, wherein an etch rate of the fillerparticles is different from an etch rate of the organic resist.